Step-in yielding heel piece for safety ski binding

ABSTRACT

A step-in heel piece for a safety ski binding which yields, in its latching position, away from the sole plate of the binding in response to the influence of external forces. The yielding heel piece improves skier comfort and accommodates various ski boot heel sole thicknesses without mechanical adjustment.

BACKGROUND OF THE INVENTION

The present invention relates to safety ski bindings. Ski bindings lockor latch to grip a ski boot, generally by gripping the edge of the soleat the heel and the toe, and hold it, and the skier whose leg is in theboot, to a ski. A binding is attached, for example, by screws, to a ski.A safety ski binding is designed to release the grip on a ski boot whenthe skiing forces on the boot and skier's leg exceed some predeterminedthreshold which threatens the safety of the skier. It is known in theart that the skiing forces may be detected mechanically orelectronically. See U.S. Pat. No. 4,291,894, issued Sept. 29, 1981 toD'Antonio and Bates.

For convenience in use, it is desirable that a safety ski binding be ofthe "step-in" type. In that type of binding, the skier cocks the releasemechanism by stepping into the binding. Other binding types requireparticular cocking actions by the skier in addition to stepping into thebinding. Some bindings require the throwing of a lever before thebinding is ready for use. The known electronic safety ski bindings, forexample the type shown in U.S. Pat. No. 4,130,296 issued Dec. 19, 1978to D'Antonio and Bates, require a skier to cock the release mechanismmanually in order to prepare the binding for use.

It has been found that a latched binding which grips the sole of a boottightly against the ski results in discomfort and fatigue for the skierduring long periods of use. Many bindings are also limited in theirlatching position to use with a particular thickness of boot sole. Achange of boot style or type usually requires a mechanical adjustment orremounting of the binding on the ski to accommodate a change in solethickness. In the present invention, these difficulties are overcome byproviding a yielding heel piece for gripping the sole of a ski bootadjacent the heel of the boot. While in its latching position, theinventive heel piece yields, i.e., moves through a limited rangerelative to the surface of the ski in response to forces havingmagnitudes below the predetermined, threatening threshold level. Theyielding movement reduces the skier fatigue that is experienced withlatched bindings that do not yield with respect to a ski. The yieldingmovement also permits a large range of sole thicknesses to beaccommodated in the latched binding without mechanical adjustment of thebinding.

SUMMARY OF THE INVENTION

The advantages of the invention in its preferred forms are accomplishedthrough a ski binding heel piece which includes a sole plate to which ahousing is connected for movement between latching and releasingpositions. The housing includes two generally parallel protrusions forengagement of the sole of a ski boot at the heel portion when the heelpiece is moved to its latching position and when it is in its latchingposition. A linkage mounted within the housing is pivotally connected tothe inside of the housing and to the sole plate of the binding. Ayielding releasable latching means permits pivoting of the housing inits latching position away from the sole plate, but prevents pivotingbeyond a limited range or arc. In the latching position, an axle along apivotal axis of the linkage is permitted limited movement, but isprevented by a lever or cam from movement beyond that range. The limitedrange of movement permitted results in yielding of the heel piece andboot for skier comfort and for the accommodation of various thicknessesof boot soles. When forces exceeding the threshold are detected, acockable release actuator is actuated freeing the axle from theinfluence of the lever or cam so that the housing can move to itsreleasing position Upon that movement of the housing, the boot sole andprotrusions at the heel piece become disengaged so that the boot isreleased from the binding.

A cocking means including elements of the linkage and latching meanscocks the release actuator when the housing is driven to its latchingposition from its releasing position. Preferably one of the protrusionson the housing acts as a pedal driven by the heel of a skier's boot tocock the release actuator. In that manner the step-in feature isachieved.

In one preferred embodiment, the linkage includes a dual pivoted, twoarm linkage. The arms are pivotally connected together along a linkageaxle. One arm is pivotally connected to the housing and the other arm ispivotally connected to a support mounted on the sole plate of the skibinding. A lever pivotally mounted on another support on the sole platehas a nose-like projection which, in its barring position, allows someswinging of the axle, but engages the axle to prevent the swinging ofthe axle to the releasing position. Upon a triggering of the bindingrelease, the lever is pivoted out of its barring position by the releaseactuator so that the nose no longer bars the swinging of the axle. Thearms of the linkage may then be fully extended to their releasingposition under the influence of biasing forces which are exerted on thehousing. When the housing is moved to its latching position, the axlebears upon the nose, pivoting the lever to drive the release actuatorinto its cocked position.

In another embodiment of the invention, the linkage includes an armpivotally connected at one end to the inside of the housing and at itsother end to an axle. A catch pivotally mounted on the housing mayengage a pin mounted on a lever engaging the release actuator andpivotally connected to a support on the sole plate. The catch includesan angular slot, having two generally straight portions, through whichthe axle passes. When relatively small forces are applied by the bootsole to the heel piece, the heel piece yields through a limited arc, butthe catch remains engaged on the pin. A cam pivotally mounted on thesupport has a cusp that confines the axle to one portion of the angularslot when the housing is in its latching position, preventing release ofthe housing to its releasing position. The permitted movement of theaxle along the cam translates to yielding of the heel piece. When aforce exceeding the predetermined threshold is present, the releasingactuator is actuated, pivoting the lever and the pin, disengaging thecatch. As a result, the axle is transferred from one portion of theangular slot to the other. The transfer allows the axle to pass over thecusp so that the linkage extends and the housing moves to its releasingposition. This action takes place under the influence of a biasing forceapplied to the housing which drives the housing to its releasingposition, disengaging the heel portion of the boot sole from the bindingheel piece.

When the housing is moved from its releasing position to its latchingposition, the axle remains in the one of the straight portions pivotingthe nose of the cam out of the way as it passes. At the same time, theaxle pivots the lever which drives the release actuator to its cockedposition. Once the axle passes the cam, the cam pivots back, pushing theaxle from one portion of the slot to the other resulting in engagementof the catch and pin. Thereby the step-in feature is achieved.

The invention is more clearly understood by reference to the drawingfigures and the detailed description of the preferred embodiments.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 is a cross sectional view of an embodiment of a ski binding heelpiece according to the invention in its latching position with no stressapplied by a ski boot engaged by the heel piece.

FIG. 2 is a cross sectional view of the heel piece of FIG. 1 in itslatching position yielding under the influence of stress applied by anengaged ski boot.

FIG. 3 is a cross sectional view of the heel piece of FIG. 1 in itsreleasing position.

FIG. 4 is a cross sectional view of the heel piece of FIG. 1 in itsreleasing position in the course of being latched.

FIG. 5 is a cross sectional view of an embodiment of a ski binding heelpiece according to the invention in its latching position with no stressapplied by a ski boot engaged by the heel piece.

FIGS. 5a, 5b, 5c and 5d are side views of elements used in the heelpiece depicted in FIG. 5. FIG. 5e is a cross sectional view of a partused in the heel piece embodiment depicted in FIG. 5. FIG. 5f is a crosssectional view of a housing used in the heel piece embodiment depictedin FIG. 5.

FIG. 6 is a cross sectional view of the embodiment of a heel piece shownin FIG. 5 just after activation of its release actuator.

FIG. 7 is a cross sectional view of the embodiment of a heel piece shownin FIG. 5 in its releasing position.

FIG. 8 is a cross sectional view of the embodiment of a heel piece shownin FIG. 5 in its releasing position in the course of being moved to itslatching position.

FIG. 9 is a transverse cross sectional view of the embodiment of a heelpiece shown in FIG. 8 taken along lines IX--IX.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Generally, in a safety ski binding, a toe piece and heel piece areprovided for grasping, respectively, the toe and heel portions of thesole of a ski boot. At least one of the pieces may be released andlatched to release and grasp a ski boot, respectively. The descriptionthat follows concerns only a releasable and latchable heel piece, but itis understood that the complete binding also includes a passive orlockable toe piece.

The heel piece described is particularly useful with an electronicsafety ski binding, i.e., one in which the forces acting on a skier'sleg are measured by electrical transducers to produce an electicalsignal corresponding to each measured force and/or torque. The signalsare processed to determine if predetermined threshold values areexceeded and represent a threat to the safety of a skier. When a threatto skier safety is detected, an electrical release signal is generatedwhich preferably activates an electromechanical device, such as an ironslug slideably mounted within an electrical coil, to cause the heelpiece to release its grasp on the ski boot sole. That is, upongeneration of a release signal there is a transition in the heel piecefrom its latching position to its releasing position. However, theinvention is not limited to electronic ski bindings. The invention maybe used with any ski binding which produces a mechanical actuation inresponse to the detection of forces which are excessive with respect tothe predetermined threshold.

In FIG. 1, a cross sectional view, taken along a medial vertical plane,of an embodiment of a yielding, step-in heel piece according to theinvention, is shown. The heel piece is shown mounted on a sole plate 101which is supported on a horizontal surface. A portion of the heelsection of a ski boot 100 which is received by sole plate 101 is shownin FIG. 1 in broken lines. A support 102 is mounted on sole plate 101and includes an axle 104. A lever 105 and a blade 106 are pivotallymounted on axle 104. Blade 106 includes an axle 107 which is fixed to ahousing 108. Housing 108 has latching and releasing positions betweenwhich it may be moved. Housing 108 includes, on its forwardmost surface,sole engaging means for engaging the sole of a ski boot. The embodimentof engaging means depicted in FIG. 1 includes two generally aligned,generally horizontal protrusions 109 and 110 for engaging the upper andlower surfaces of the heel portion of the sole of a ski boot.Preferably, the separation of protrusions 109 and 110 is greater thanthe maximum thickness of the boot sole expected to be encountered. Asexplained further below, the heel piece can accommodate boots having anysole thickness that is thinner than the separation of the protrusions.

In its latching position, shown in FIG. 1, housing 108 may be movedthrough a limited arc. A linkage support 103 is mounted on sole plate101 within housing 108 toward the forward portion of the heel piece,i.e., toward the front tip of a ski on which the binding is to bemounted. By contrast, support 102 is mounted toward the rear of the ski.

Support 103 pivotally supports an axle 115, which is horizontal in FIG.1, to which a linkage is connected. A first link 113 of the linkage ispivotally connected at its respective ends to axle 115 and to an axle114. Axle 114 is horizontal in FIG. 1 and lies to the rear of support103. Another link 112 of the linkage is pivotally connected at itsrespective ends to axle 114 and an axle 111. Axle 111, which ishorizontal in FIG. 1, is firmly fixed in housing 108. As shown in FIG.1, in the latching position, links 112 and 113 partially overlap,closing somewhat in the manner of scissor blades pivoted on axle 114. Arearward extension of support 103 near the sole plate carries anotheraxle 116, horizontal in FIG. 1, on which is pivotally mounted urgingmeans in the form of a cam 117. Cam 117 has an arcuate surface towardthe front of the ski which axle 114 may follow. The arcuate surface ofcam 117 guides axle 114 during movement of housing 108 to its latchingposition. Lever 105 and cam 117, blade 106 and links 112 and 113 are allpreferably made from thin plate or thick sheet metal stock, for example,by punching.

Lever 105 extends downward into a chamber within sole plate 101 where arelease actuator 122 protrudes from the rearward direction of thebinding. A shaft 127 extends horizontally from lever 105 and is incontact with the end of actuator 122. A nose-like projection 123 onlever 105, defined by a lower surface 124 and an upper surface 125,extends toward the forward part of the heel piece, that is, in thedirection of the front of a ski on which the heel piece is mounted.

Biasing forces are applied to various elements of the heel piece shownin FIG. 1 by conventional means such as helical springs, generally notshown. A helical spring 118 bears upon axle 104 and cam 117, urging thecam toward the front of the heel piece so that it bears on axle 114.Blade 106 has a blade moment 119 applied to it in a clockwise directionas viewed in FIG. 1. The rear portion of blade 106 extends downwardtoward sole plate 101 and includes at its tip a striking surface 120which contacts support 102 when the heel piece is in its releasingposition. A lever moment 126 is applied to lever 105, urging the levercounterclockwise in FIG. 1, to maintain contact between shaft 127 andrelease actuator 122. Housing 108 is under the influence of a housingbiasing moment 121, clockwise in FIG. 1, which urges the housing towardits releasing position.

In FIG. 1, the heel piece embodiment is in its latching position andboot 100 rests flat on the sole plate 101 without any stress tending tolift the boot heel from the sole plate. Nose 123 of lever 105 isretracted and does not contact any other element. In FIG. 2, ski boot100 has been tipped forward, so that its heel is raised off sole plate101. The top edge of the boot sole at its heel contacts protrusion 109raising housing 108, at its forward end, off, i.e., away from, soleplate 101. The lifting of the housing causes axle 114 to begin anarcuate path toward the rear of the heel piece and away from sole plate101. As it follows that path, axle 114 eventually engages nose 123 oflever 105. Lever 105 blocks further movement of axle 114 and movement ofhousing 108 beyond a limited range. In its latching position, lever 105thereby permits the linkage and housing 108 to yield, but prevents thehousing from assuming its releasing position. In the absence of anyforce tending to raise boot 100 of sole plate 101, spring 118 pushes cam117 forward. Cam 117 bears on axle 114 urging it forward tending tomaintain housing 108 in its latching condition shown in FIG. 1. Thestrength of spring 118 determines the force required to produce yieldingof housing 108 while it is in its latching position.

As FIGS. 1 and 2 make clear, the heel of the ski boot may raise off andlower onto sole plate 101 without release of the heel piece. Thistolerance or "play" is helpful in avoiding skier fatigue. Moreover, thesame tolerance allows boot soles of various thickness to be used withthe heel piece. A sole as thick as the separation of protrusions 109 and110 may be used or a much thinner sole may be used. The only consequenceof a sole thickness change is to reduce or increase the range of theyielding movement by housing 108.

In FIG. 3, the heel piece embodiment is shown in its releasing position.A release signal has been generated and release actuator 122 has beenthrown forward. Actuator 122 has pushed shaft 127 forward so that lever105 is pivoted, clockwise in FIG. 3, against the urging of biasingmoment 126. As a result of the pivoting, nose 123 is retracted andcannot block the movement of axle 114. Therefore housing 108, under theinfluence of biasing moment 121, moves to its releasing position andlinks 112 and 113 are extended. Simultaneously with said movement ofsaid housing 108 (which occurs about said axle 107) blade 106 is movedby means of a spring which is schematically represented by an arrow 119in the direction of the arrow head. Typically, said spring is arrangedbetween support 102 and blade 106. As housing 108 reaches its releasingposition its lowermost rear edge strikes the rear portion of blade 106.The movement of housing 108 is stopped when striking surface 120 ofblade 106 strikes support 102. Blade 106 is then pinched between housing108 and support 102 and the engagement between protrusions 109 and 110and the sole of a ski boot is released.

FIG. 4 shows the heel piece embodiment in the course being latched afterit has been released. The heel of ski boot 100 engages protrusion 110 ofhousing 108 as a pedal and drives it down, i.e. toward sole plate 101.Axle 114 is thereby caused to follow the arcuate portion of cam 117 andcontacts the top, i.e., curved portion 125, of nose 123 on lever 105, asshown. Lever 105 is pivoted on axle 104, counterclockwise as seen inFIGS. 1 through 4. Shaft 127 thereby pushes release actuator 122 backinto its cocking position, and a bit beyond it, as axle 114 finallyslips past nose 123. Once axle 114 passes nose 123, the heel piece islatched in its latching position. The biasing force on cam 117 thenpushes axle 114 back to the latching position shown in FIG. 1. Actuator122 is preferably normally biased out of its retainer and has a detentor latch means to hold it in place once the actuator is returned to itscocked position. Such latch means is described in a U.S. patentapplication filed in the European Patent Office according to the PatentCooperation Treaty on Aug. 17, 1982 in the name of one of theco-inventors of this application.

It should be noted that during the last phase of the step-in movement(transition from the position of FIG. 4 to the position of FIG. 1) alsoa pivotal movement of blade 106 occurs. Said movement takes place in adirection opposite to the direction of arrow 119 and causessimultaneously a movement of said housing 108 towards said ski boot 100and forces said ski boot 100 against the toe piece.

Another preferred embodiment of the step-in yielding heel pieceinvention is shown in FIG. 5 in a cross sectional view along atransverse plane offset from the middle of the heel piece. Among thedifferences between the embodiments of FIGS. 1 and 5 is that theembodiment of FIG. 5 slants upward toward the rear. Accordingly, thesole plate 130 of the heel piece has an angled portion 131. Again, a skiboot 100 is shown in broken lines. The embodiment of the invention shownin FIG. 5 is symmetrical about a medial vertical plane. Some of theelements of the embodiment are shown in broken lines in FIG. 5. One ofeach of the symmetricallly placed elements is shown in FIGS. 5a, 5b, 5cand 5d. It is understood that the symmetrical elements are describedwith respect to the depicted portion and that the description alsoapplies to the symmetrical portion not shown. A cross section of aU-shaped element used in the embodiment is shown in FIG. 5e. A crosssection of the housing 140 employed in the embodiment is shown in FIG.5f. An understanding of the placement of the pairs of parts and thesymmetrical parts within housing 140 is aided by reference to FIG. 9, across sectional view, transverse to that of FIG. 5, taken along lineIX--IX of FIG. 8. FIG. 9 likewise shows the location of the sectioning,along line VIII, which is the basis of the views of FIGS. 5, 6, 7 and 8.

The embodiment of FIG. 5 includes a support means or retainer 133 havinga bridge section or a base plate 135 by which the embodiment ismaintained on angled portion 131 of a sole plate 130. Base plate 135 isattached to angled sole plate portion 131 by a pin or screw 132 and aspring lever 134 which extends from screw 132 and through an arcuateslot in portion 131. This attachment arrangement permits someside-to-side movement of the heel piece when housing 140 is unlatched,against the bias of a spring lever 134. Means described below preventsuch sideways swivelling when housing 140 is latched.

Housing 140 includes two generally parallel protrusions 109' and 110' onthe forward portion of housing 140 for engaging the sole of a ski boot.Plate 135 forms the base of the square cornered U-shaped retainer 133for supporting the axles which pass through other elements. A crosssectional view of retainer 133 depicting one arm 139 of the U-shape isshown in FIG. 5e. Retainer 133 is described with respect to arm 139which is shown in FIG. 5 and 5e; but it is understood that both arms ofthe U are symmetrical and that each slot, hole and axle described forarm 139, also appears in or passes through the other arm. As notedabove, retainer 133 is fixed to the ski. Arm 139 carrier axles 141 and142. Housing 140 is pivotally mounted on axle 141. Retainer arm 139 alsocontains an arcuate slot 148 at its upper rear portion through which ashaft 147 passes. Shaft 147 is fixed in housing 140. Slot 148 has acentral axis along an arc of a circle centered on axle 141. Near itsupper forward extension, retainer arm 139 has an aperture through whichan axle 142 extends. At the forward portion of arm 139 below axle 142,i.e., toward base plate 135, retainer arm 139 contains an arcuate slot165 which has a central axis lying on an arc of a circle centered onaxle 142. At the forward part of retainer arm 139, near plate 135, arm139 contains an arcuate slot 166 having a central axis lying on an arcof a circle centered on axle 142. On the extreme forward portion ofretainer 133, arms extend downward and forward terminating in asymmetrical pair of fingers. One of the pair, a finger 136 is shown inFIGS. 5 and 5e. The fingers lie below plate 135 within a chamber 138 inthe binding in which a release actuator 150 lies and moves upon receiptof a release command. The fingers serve as guides for the moving partswithin the chamber. Said fingers are quided under and by means of atransversely extending part 137. Said part 137 extends across saidchamber and is an integral portion of said sole plate 130.

A shaft 155 fixed to housing 140 carries a pivoting catch 154. Catch 154includes an angular slot 163 having two intersecting, generally straightportions for receiving and pivotally engaging axle 161. A peripheralopening 158 in catch 154 forms a hook for releasably engaging aprojecting pin 153. Pin 153 is mounted on a lever 143 which is pivotallyconnected to axle 142. Catch 154 engages pin 153 when the heel piece isin its latching position. One of the symmetrical sides of lever 143 isshown in FIG. 5d. A bridging portion 149 joining the two halves of thelever 143 is indicated by the broken line in FIG. 5d and is most clearlyseen in FIG. 9. Lever 143 includes an arcuate slot 164 having a centralaxis lying on an arc of a circle centered on axle 142. The lowestforward portion of lever 143 includes an arm 151 terminating in bridgingportion 149 which, in the assembled heel piece, extends into the chambercontaining release actuator 150. Release actuator 150 includes a recessengaged by bridging portion 149. When release actuator 150 is triggeredand moves, bridging portion 149 is carried along by the actuator.Thereby, lever 143 pivots about axle 142. Pivoting of lever 143 causespin 153 to move and thereby pivot the catch 154 clockwise (cf. FIG. 5a)against the force exerted by a spring 156. Lever 143 has a stop 151(actually, because of the mentioned symmetrical design, there are twostops 151 at opposite sides of the bridging portion 149) whichcooperates with an element 152 located above actuator 150 for preventingthe sideways swivelling of retainer 133 about pin 132 when the bindingis in the latched condition.

As FIG. 9 shows, a catch 154 is mounted against each inside wall ofhousing 140. Next to and between the catches, the retainer arm 139 ismounted. Moving further inside housing 140 from each side, two levers143 followed by two cams 144 are pivotally mounted on axle 142. One ofthe cams 144 is shown in FIG. 5c. It includes a projecting pin 145 whichin the assembled heel piece protrudes through arcuate slot 164 in lever143 into arcuate slot 165 in retainer arm 139. Cam 144 includes a cuspon its forward edge. The cusp is formed by two complex curvedintersecting edges. Finally, the innermost of the symmetrical elementsshown in FIG. 9 is a linkage arranged in housing 140. A link 160, whichis part of the linkage, is shown in FIG. 5b. The top, i.e., the partfurthermost from plate 135 in the assembled heel piece, of link 160 ispivotally attached to an axle 159 which is retained near the inside topof housing 140 by a support depending from housing 140. The opposite endof link 160 includes a hub or roller 162 through which the axle 161 ofthe linkage passes for pivotal connection of arm 160 to catch 154. Hub162 adds thickness to link 160 so that hub 162 may bear upon and ridealong the guide provided by the curved surfaces of cam 144. Axle 161also passes through the angular slot in catch 154. A spring 146 biasesshaft 147, mounted in housing 140, and pin 145, on cam 144, apart,urging housing 140 to move toward its releasing position.

In FIG. 5, ski boot 100 is shown placed on sole plate 130 with no stressbeing applied to the heel piece by the boot. Protrusion 109' engages thetop of the boot sole and restrains it toward sole plate 130. Because ofthe angle in the binding, the sole plate includes a chamber 138 forreceiving heel engagement protrusion 110' in the latching positionshown. The thickness of the boot sole determines how much of protrusion110' lies within chamber 138. As explained before, various thicknessboot soles may be accomodated since the heel piece yields to some degreeunder upward stress. In the latching position, shown in FIG. 5, shaft147 is in the forward portion of arcuate slot 148 in retainer arm 139.Hub 162 is separated from and lies below the cusp of cam 144 within acut out portion of lever 143 intended to receive it. Axle 161 lies inthe upper straight portion of angular slot 163 of catch 154. Opening 158in catch 154 engages pin 153. Axle 161 is held down, toward sole plate130, along with link 160 and housing 140. This is achieved by means ofspring 156 which urges catch 154 counterclockwise into its normalposition shown in FIGS. 5 and 7.

When upward stress is placed on the heel piece by the boot sole, housing140 yields, but does not move all the way to its releasing position. Thereleasable latching means yields, but does not release. The upward forcepulls link 160 away from sole plate 130. Hub 162 of latch 160 engagescam 144 and rides up said cam 144. Because of the cusp on cam 144, saidcam 144 is pushed toward and against spring 146 as housing 140 rises.The forward movement of hub 162 is resisted by the engagement of catch154 on pin 153, so that the cusp on cam 144 confines axle 161 to one ofthe straight portions of angular slot 163. Thereby axle 161 is preventedfrom moving beyond a limited range. In this way, housing 140 isprevented in its latching position from moving to its releasingposition, but the latching means yields to allow some movement ofhousing 140 while it is in its latching position. Spring 146 ensuresthat cam 144 remains in contact with hub 162. As one skilled in the artwill appreciate, the parts described must be shaped and located so as tocooperate as described to achieve the advantages of the invention.Retainer 133, bracket 143, cam 144, catch 154 and arm 160 are preferablypunched from, thick sheet metal or thin metal plate. Pins and hubs areadded by conventional means.

When the binding detects forces exceeding the predetermined safetythreshold, release actuator 150 is triggered and thrown forward. In itsmovement, actuator 150 carries with it the bridging portion 149 of lever143. The instant after the actuation of actuator 150 is shown in FIG. 6.The pivoting forward of lever 143 rotates catch 154 about axle 155against spring 156. Catch 154 is then lifted away from sole plate 131under the influence of the bias on housing 140. Axle 161 is therebyforced by the forward force applied by the cusp on cam 144 from onestraight portion of angular slot 163 in catch 154 to the other. Cam 144resists moving out of the path of hub 162 because spring 146 applies aforce to cam 144 which is larger than the force applied by spring 156 tocatch 154 and in turn to hub 162. The change in position of axle 161from one straight portion of slot 163 to the other allows axle 161 tomove forward and pass by the cusp. This chain of movements is driven byspring 146 which maintains a moment, clockwise as viewed in FIG. 6, onhousing 140 tending to move it toward its releasing position. In themovement depicted in FIG. 6, shaft 147 has begun to move within arcuateslot 148 of retainer arm 139 from a forward to a rearward position asthe housing moves toward its releasing position.

FIG. 7 shows housing 140 in its releasing position. After the release,housing 140 moves until shaft 147 travels as far as possible in arcuateslot 148; then further movement of housing 140 is blocked and theposition shown is achieved. That is, slot 148 acts as a stop means forstopping movement of the housing just as blade 106 did in the otherdescribed embodiment. After hub 162 is in a position away from said cam144 (cf. FIG. 7), said catch 154 moves, due to spring 156, back into itsnormal position, whereby axle 161 is also moved into the upper straightportion of angular slot 163.

The pivotal movement of lever 143 frees the stops 151 from element 152(said element 152 being arranged above release actuator 150 on angledportion 131 of sole plate 130, so that the support means 133 can pivotagainst the force of spring 146 in a rightward and leftward directionrespectively. Said pivotal movement takes place about pin 132 with apredetermined amount limited by chamber 138. This allows for a saferelease of the ski boot specifically in the instance of a lateralrelease, i.e. a release where only a torque is present.

In FIG. 8, the heel piece is shown being latched by insertion of a skiboot 100. The sole of the boot presses down on protrusion 110' so thatit is a pedal driving housing 140 toward sole plate 130. Hub 162 pressesagainst cam 144 and, since hub 162 is now above the cusp on cam 144, hub162 also exerts pressure on spring 146. Cam 144 rotates about axle 142against the urging of spring 146, to allow hub 162 to pass by the cusp.At the same time, hub 162 is bearing on the front edge of lever 143pushing it rearward so the release actuator 150 is pushed back into soleplate position 131 slightly beyond the latched position of the actuator150. The actuator is then allowed to move forward to its latchedposition, being restrained by the latch or detent means associated withthe release means. Such a latch means is described in the U.S. patentapplication filed according to the PCT previously referred to herein.That is, lever 143, under the influence of the driving force of ski boot100 cocks actuator 150 so that the binding has step-in convenience. Oncehub 162 passes the cusp on cam 144, cam 144 resumes the position it hasin FIG. 5. With the counterclockwise rotation of housing 140, pin 153comes into engagement with peripheral opening 158.

In both of the described embodiments, and in other embodiments of theinvention, it is convenient to provide a means for release of the heelpiece by the skier in the absence of a threatening force. In the case ofan electronic binding, the elective release may be conveniently actuatedby a push button switch so that the circuitry causes the releaseactuator to be thrown.

The invention has been described with reference to certain preferredembodiments. Various additions and modifications will occur to thoseskilled in the art. Accordingly, the scope of the invention is limitedsolely by the following claims.

In principle, the invention relates to a safety ski binding comprisingan electronic circuit which actuates an electromagnet. At least onetransducer means is provided which determines the forces and/or torquesacting upon the leg of a skier. As soon as a predetermined thresholdvalue is reached, said electromagnet is actuated. The electromagnetreleases the latching means of a binding portion (housing means) fromits latching position. Specifically, the binding portion is a heelholding means. Said binding portion is spring-loaded by means of atleast one spring 121, 146 in a direction of its opening position. Saidbinding portion is held in its latching position by means of saidlatching means 105; so as to release said latching means, a releasemeans 122, 150 is provided which can be actuated through the force of atleast one energy storing means, preferably in the form of a spring; thatforce is a multiple of the force provided by the electromagnet. Saidbinding portion 108, 140 comprises a closing pedal 110 which is theinitial or first member of a kinematic chain which spefically providesfor a cocking of the energy storing means when a step-in action occurs.Specifically a cocking member is provided in the form of a lever 105,143 arranged parallel to the binding portion. Said lever 105, 143comprises a cam portion for cooperation with a cocking element 114, 162connected with said binding portion. Preferably, the invention providesfor means for creating a resilient range of movement for the bindingportion (i.e. the housing 108, 140) in the latching position of saidportion.

Preferably, a cam disk 117, 144 is loaded by means of a spring 118, 146for cooperation with said cocking element, in particular a roller 114,162. Said roller is arranged at the free end of a lever 112, 160 whichis supported in the binding portion parallel to the pivot axis 107, 141thereof.

It should be noted that all features disclosed in the description, theclaims and the drawings are considered to be of inventive character, beit that they are taken individually or in combination.

In summary, the ski binding of the invention provides for automatic"step-in" cocking of the energy storing means of the release means and aresilient or elastic accomodation of soles having varying thicknesses orhaving snow adhered thereto. Moreover, the means 118, 146 providing theresilient accomodation may also be cocked during said "step-in" action;also at the same time the opening spring 146 for the housing may becocked simultaneously.

We claim:
 1. A heel piece for a step-in, yielding electronic ski bindingfor releasably latching a ski boot from the binding upon actuation of acockable release actuator, said heel piece comprising:sole plate meansfixable to ski; housing means including sole engaging means for engagingthe sole of a ski boot; connection means interconnecting said housingmeans and said sole plate means for movement of said housing meansbetween latching and releasing positions, said connection meansincluding a first link arm having first and second ends, said first endbeing pivotally connected to axle means and said second end beingpivotally connected to said housing, said axle means movable along apredetermined path as said housing means moves between said latching andreleasing positions; cam means pivotal about an axis stationary withrespect to said base plate, said cam means including surface meansbearing on said axle means for urging said axle means to move saidhousing means toward its latching position; latching lever means,separate from said cam means, pivotal about an axis stationary relativeto said sole plate means for releasably latching said housing means inits latching position, said latching lever means including surface meansfor engagement with said axle means, said lever surface means operativewith said cam surface means for preventing movement of said housingmeans beyond a limited range when said housing is in its latchingposition; and cocking means for cocking the cockable release actuatorwhen said housing means is moved to its latching position.
 2. Theinvention of claim 1 wherein said latching lever means comprises levermeans pivotally connected to said sole plate means and including a nosefor engaging said axle means.
 3. The invention of claim 2 wherein saidlever means is engageable by the release actuator for pivoting saidlever means upon actuation of said actuator to prevent engagement ofsaid nose and said axle means when said housing means moves from itslatching position to its releasing position.
 4. The invention of claim 2said lever means is engageable by the release actuator, and said cockingmeans comprises said axle means for engaging said nose and for pivotingsaid lever means to cock said actuator when said housing means movesfrom its releasing position to its latching position.
 5. The inventionof claim 1 wherein said connection means comprises axle means mounted tosaid housing means, catch means pivotally mounted on said housing meansfor engaging pin means when said housing means is in its latchingposition, and an arm having first and second ends, said first endcarrying said axle means and said second end being pivotally connectedto said housing means.
 6. The invention of claim 5 wherein saidreleasable latching means comprises support means mounted on said soleplate means, lever means pivotally mounted on said support means forengaging said release actuator, pin means mounted on said lever meansfor being engaged by said catch means when said housing means is in itscatching position and for releasing said catch means upon actuation ofsaid release actuator.
 7. The invention of claim 6 wherein said catchmeans includes a peripheral opening for engaging said pin means.
 8. Theinvention of claim 6 said releasable latching means further comprisingcam means pivotally mounted on said support means, for engaging saidaxle means to prevent said housing means from moving beyond said limitedrange when said housing means is in its latching position.
 9. Theinvention of claim 8 wherein said catch means includes a slot having twointersecting portions, said axle means passing through said slot,wherein said cam means includes cusp means for urging said axle means,and wherein said axle means is movable from one of said portions to theother upon actuation of said release actuator, due to the rotation ofcatch means.
 10. The invention of claim 9 wherein said cam meansincludes cusp means for providing said axle means and said housing meanswith a limited range of resilient movement when said housing is in itslatching position.
 11. The invention of claim 6 wherein said cockingmeans includes said axle means for engaging and pivoting said levermeans to drive said release actuator to its cocking position when saidhousing means is moved from its releasing position to its latchingposition.
 12. The invention of claim 11 wherein said cocking meansfurther includes said catch means and cam means, said cam means beingpivotally mounted to said support means for engaging said axle meanswhen said housing means is moved from its latching position to itsreleasing position, and said catch means includes a slot, said axlemeans passing through said slot.
 13. The invention of claim 12 whereinsaid slot includes two intersecting portions and said cam means includescusp means upon which said axle means is urged so as to pivot said cammeans against spring means when said housing means is being moved fromits releasing position to its latching position.
 14. The invention ofclaim 1 and further comprising blade means pivotally mounted on saidsole plate means, said housing means being pivotally mounted on saidblade means for abutting structure fixed on the ski to limit themovement of said housing means in the releasing position.
 15. Theinvention according to claim 14 and further comprising spring means fora biasing said blade means into abutment with structure fixed on the skiin response to movement of said housing means to the releasing position.16. The invention of claim 1 and further comprising support meansfixable on a ski for supporting said housing means for movement betweenlatching and releasing positions and swivel means for enabling limitedmovement of said support means from a straight position aligned with thesole plate to positions transverse to said sole plate.
 17. The inventionof claim 16 and further comprising spring lever means for urging saidsupport means towards the straight position.
 18. The invention of claim16 and further comprising lever means mounted on said support means whensaid housing means is in the latched position.